A counterbore bit is a cylindrical shaped device that can enlarge a coaxial hole on the same tool or surface. This type of counterbore drill hole is commonly used on objects that are made for screws, so they can rest on a flush level with the surface. Our carbide tipped counterbore provides durability and excellent longevity. Our counterbore selection has many different dimensions to drill through metal thicknesses. For more types of drilling applications, we have a wide selection of port tools to choose from.